In a reflective liquid crystal display apparatus, it is known to add an auxiliary light source to illuminate the reflective liquid crystal display apparatus from an edge thereof (refer, for example, to patent document 1).
FIG. 1 is a diagram schematically showing one example of such a reflective liquid crystal display apparatus.
As shown in FIG. 1, reflective liquid crystal display apparatus 1 comprises a liquid crystal panel 2, an LED light source 30, and an IC circuit 40 for driving liquid crystal panel 2. Liquid crystal panel 2 comprises a first transparent substrate 21, a second transparent substrate 22, a polymer dispersed liquid crystal 4 sandwiched between the first and second transparent substrates, a sealing member 26 for sealing the polymer dispersed liquid crystal 4 therebetween, a first transparent electrode 28 disposed on the inside of first transparent substrate 21, a prism 3 disposed on top of first transparent substrate 21, a second transparent electrode 27 disposed on the inside of second transparent substrate 22, and a reflector 25 disposed on the outside of second transparent substrate 22.
In a region X1 where voltage is applied between the first and second transparent electrodes, Polymer dispersed liquid crystal 4 allows light to freely pass through it (non-scattering mode), and the region thus appears black except for a portion thereof where the light is reflected from the rear reflector. On the other hand, in a region X2 where no voltage is applied, the polymer dispersed liquid crystal 4 scatters the light (scattering mode), and the region thus appears white.
When light introduced from the LED light source 30 into liquid crystal panel 2 is reflected by prism 3 and enters the region X1, the light passes through the liquid crystal layer (non-scattering mode), is reflected by the reflector 25, and emerges on the viewer side (see M1). As a result, the reflected light is observed on the viewer side of the region X1 where voltage is applied.
On the other hand, when light introduced from the LED light source 30 into liquid crystal panel 2 is reflected by prism 3 and enters the region X2, the light is scattered in the liquid crystal layer (see P1) (scattering mode), and the reflected light is not directly observed on the viewer side (see M2). As a result, the region X2 where no voltage is applied appears white, since the reflected light emerges as scattered light which is observed on the viewer side.    Patent document: JP 2003-57645 A